Photographic material



I Patented Nov. 21, 1939 UNITED STATES PATENT OFFICE- PHOTOGRAPHIG Walter Frankenburger, Ludwigshafen, and Hermann Schulz, Heidelberg, Germany, assignors, by mesne assignments, to' Agfa Ansco Corporation, Binghamton, N. Y., a corporationo! A Delaware No Drawing. Application November 11, 1937,

fggiial No. 174,058. In Germany November 19,

1 Claim. (Cl. 95-8) halation layers or filter layers and for coloringv photographic emulsions. There exists in a more or less strong degree the possibility that the coloring substances used will affect the photographic silver halide emulsions when first added or during further treatment. It is known that the properties of photographic silver halide emulsions are unfavourably influenced even by very small proportions of foreign substances. In particular the sensitivity of the emulsion may be considerably lowered by many soluble dyestuffs and also, indeed, by pigments which are practically insoluble and might therefore be expected to have no effect, for example colored lakes produced by precipitation of basic triphenylmethane dyestufl's or xanthene dyestufl's with phosphotungstic acid and pigments of the indigo series and indan-.

threne series. The choice of suitable dyestufls applicable for the productionof photographic materials is small, especially thoseof blue to reen tint.

This invention is based on the observation that the phthalocyanines and their metal compounds,

among which are dyestufl's of bright blue, blue green and green tints, are especially suitable for use in photographic silver halide emulsions.

These phthalocyanines are useful in all cases in which thephotographic material is one wherein there is the possibility that the dyestuff may act upon the photographic silver halide emulsion;

more especially the sensitivity of the photographic emulsion is only very slightly influenced by the said dyestuffs.

These Y dyestufls, especially the sulfonated phthalocyanines which are soluble in water, may be used for making colored layers of all kinds, for example fllter layers,anti-halation layers, colored emulsion layers, whether single layers 'or multi plelayers, coating layers or the like. The phthalocyanines are also suitable for blueing barlte paper, particularly copper phth'alocyanines, since an emulsion applied to :barite paper is not uniavourably influenced. The insoluble phthalocyanines, for instance phthalocyanines which are free from metal, are especially useful i'or coloring emulsions for the purposes of color photography. Information concerning phthalo cyanines is to be found "in the work of Linstead.

and his co-workers in the Journal of the Chemical Society, vol. 136 (1934) pages 1016 and following'.\ 1

What we claim is:

A photographic, material comprising a silver halide emulsion layer containing a dye selected from the group consisting of a phthalocyanine, a suli'onated phthalocyanine and a metal phthalocyanine.

WALTER HERMANN SCHULZ. 

